The present invention is a turbo-rocket thruster which is a reaction thrusting power plant capable of accelerating a spacecraft to sub-orbital and orbital speeds and altitudes. The principal use of the present invention is on aircraft and spacecraft having a large reservoir of gaseous fuel, which may be combustible by oxidation or in some other exothermic reaction, particularly a combination airship and spacecraft.
The preferred gaseous fuel for the turbo-rocket thruster is a gaseous fuel that contains hydrogen gas. The reservoir containing such gaseous fuel may be the gas retaining structures of an airship, such as gas bags, wherein the gaseous fuel serves as the lifting gas.
The types of propulsion systems which create a propulsion force known as thrust to propel vehicles at high altitudes are the rocket motor and the jet engine. The propulsion force is the reaction force arising from increasing the backward momentum of a mass by the action of the propulsion system. In the case of the rocket motor, the rearward ejected mass comes from the propellant chemicals carried with the vehicle, and the backward momentum from the reaction between those propellant chemicals. In the case of the jet engine, addition of heat energy to a controlled flow of air passing through the jet engine increases the backward momentum of the airflow.
Some of the features of the present invention disclosed here as the "turbo-rocket thruster" relate to features of both jet engines and rocket motors. The use of the hyphenated description "turbo" in the present invention relates to the inclusion in the present invention of a turbine compressor driven by a gas turbine, as in a jet engine. The noun "rocket" relates to the fact that the present invention involves the rearward ejection of mass which may come from the chemical reaction of propellant chemicals which are carried with the vehicle, in this case a reservoir of fuel in a gaseous state and a reservoir of oxidizer. Unlike conventional jet engines which compress intaken air, the turbine compressor of the turbo-rocket thruster is used to compress intaken gaseous fuel, which may not otherwise have sufficient density for efficient combustion, to a state of greater density. Also, unlike conventional jet engines, the combustion of the gaseous fuel compressed by the turbine compressors takes place with a stored oxidizer which is injected into the compressed gaseous fuel stream.
The use of gaseous hydrogen as fuel for power plants which compress air with turbine compressors is known from U.S. Pat. No. 5,012,640, The Combined Air-Hydrogen Turbo-Rocket Power Plant. The power plant disclosed in that patent, however, uses evaporating liquid hydrogen to drive a turbine which powers a turbine compressor to compress air into which gaseous hydrogen is injected for combustion, and does not use the turbine compressor to compress the hydrogen. Also, that power plant does not use stored oxidizer to burn the hydrogen, but uses the air which has been compressed for such combustion.
The present invention has elements that are covered generally by class 60, power plants, particularly subclass 246.